Square Mile to Hectare

The Public Land Survey System (PLSS), established by the Land Ordinance of 1785, divided US territory into 6-mile × 6-mile townships (36 mi²) and 1-mile × 1-mile sections (1 mi², = 640 acres). This grid underlies property deeds, county boundaries, and road layouts across most of the western US. Switching to km² would require legal redefinition of millions of property descriptions — a transition with no political appetite.

Manhattan borough is 22.83 mi² (59.1 km²), making it one of the most densely populated places on Earth at about 71,000 people/mi². The island itself (excluding water area) is about 13.4 mi². For comparison, the entire city of New York is 302.6 mi², of which 36% is water. Central Park occupies about 1.3 mi² — nearly 6% of Manhattan's land area.

Alaska is by far the largest at 663,268 mi² — over twice the size of Texas (268,596 mi²). Alaska is so large it would be the 18th largest country in the world if independent. For perspective, the entire Lower 48 states fit within Alaska about 5 times over in land area. Alaska also has the longest coastline of any US state at 33,904 miles.

One square mile is a square about 1,609 m (just over a mile) on each side. A standard city grid: in Chicago, the city blocks are laid out on a 1-mile square grid, so 16 standard blocks (4 × 4) = 1 mi². Walking the perimeter of 1 mi² takes about 1 hour at a moderate pace. In rural areas, US county road grids typically run every mile, creating a visible 1 mi² checkerboard visible from aircraft.

The PLSS divides most land west of the Appalachians into a grid of 6×6 mile townships, each split into 36 sections of 1 mi² (640 acres). Established by the Land Ordinance of 1785, it still defines property boundaries for roughly 1.5 billion acres across 30 states. County roads in the Midwest often follow PLSS section lines, creating the visible checkerboard pattern from the air. The system predates metric adoption and is so embedded in US land titles that converting to km² would require re-recording tens of millions of deeds.

A standard FIFA pitch (68 m × 105 m = 7,140 m²) means about 1.4 pitches per hectare. Phrased the other way: 1 hectare contains roughly 1.4 football pitches — making the hectare a convenient mental reference. The "football pitch" comparison is used so frequently in British journalism that the Guardian style guide actually discourages it as a cliché.

One hectare = 2.471 acres. The acre (4,047 m²) is older and derived from the area a yoke of oxen could plow in one day. The hectare (10,000 m²) is a clean metric unit derived from the are. The EU officially uses hectares for agricultural policy (Common Agricultural Policy payments are per hectare). The US still uses acres for real estate and land sales in most contexts.

Yield varies enormously by crop and region. One hectare of wheat in the UK averages about 8–9 tonnes per year. Maize in the US Corn Belt yields 10–12 tonnes/ha. Rice paddies in tropical Asia produce 4–6 tonnes/ha. Potatoes yield 40–50 tonnes/ha — the caloric density argument that explains why European populations could be sustained by potato-farming Ireland's limited arable hectares before the famine.

Yes, universally. Even countries that have otherwise fully adopted SI still use hectares for land area — it fills the gap between m² (too small for farms) and km² (too large). The 1979 BIPM publication accepted the hectare as a 'non-SI unit accepted for use with SI' alongside the liter and tonne. No country has replaced it with km² for agricultural use, because km² is too coarse (1 km² = 100 ha) for typical farm sizes.

King Charles III is the largest private landowner in the world through the Crown Estate, at approximately 264,000 ha in the UK alone (not including Commonwealth realms). In Australia, the Kidman family's historic cattle station holdings exceeded 10 million ha. In the US, the largest private landowner is John Malone with roughly 880,000 ha (2.2 million acres). For comparison, the entire Netherlands is 4,150,000 ha.